120 Agricultural Experiment Station^ Ithaca, N. Y. 



unsprajed orchards, may be considered as one of the prime factors 

 which brought about the trouble. Since such an unusual amount 

 of rain fell, this excess of moisture alone may have brought it on. 



When we come to sprayed orchards, the severity of the rust 

 increases, probably on account of the chemicals used, and not in 

 consequence of the water applied, as this amount is comparatively 

 small. One of the most severe cases of rust noticed was in the 

 orchard of John W. Spencer, Westfield, N. Y., and these trees had 

 been thoroughly sprayed with the Bordeaux mixture and London 

 purple. In the trees sprayed by this station the rust appeared ta 

 increase with the number of treatments, and those which were 

 sprayed with the Bordeaux mixture made with the potassium fer- 

 rocyanide test showed the discoloration most strongly. Mr. Spencer 

 used the same test in making his Bordeaux mixture and from all 

 appearances the trouble has been aggravated by the use of the chem- 

 ical. In the orchard of a prominent fruit grower a pear crop was 

 practically ruined apparently by the early use of Bordeaux mixture 

 prepared with the aid of this test. Fully seventy-five per cent, of 

 the fruit fell to the ground soon after the application was made, 

 while in a neighboring orchard containing similar varieties, the 

 the fruit remained upon the trees.* (See initial illustration, p. 105.) 

 The test, therefore, would seem to be unsafe unless more lime is 

 added than appears to be necessaary. The lime will not prevent 

 the trouble, but it may assist in lessening its severity. The formula 

 given on page 110 seems to be as satisfactory as any yet proposed in 

 this country. I have learned., however, that in some parts of Italy 

 a much more dilute mixture is used on grapes, with entire success. 

 The formula recommended in the past by this station is made 

 approximately of a one and eight-tenths per cent. (1.8 per cent.) solu- 

 tion of copper sulphate, considering the crystals as weighing 6 

 pounds and the forty gallons of water 333 pounds. The Italian 

 mxiture calls for only seven-tenths of one per cent. (.7 per cent.) 

 which is equivalent to diluting our mixture to about 104 gallons. 

 Applications made with such a fungicide may not encourage rust, 



*iiee ii\so Garden and Forest, vii. p. 456 for a more complete account of this 

 orchard. The danger of using the Bordeaux mixture made with the ferrocyanide 

 test, was iudicated in Bull. 74, p. 382 and 84, p. 12. At about the same time 

 Fairchild's bulletin upon the Bordeaux mixture (Bull. 6, Div. Veg. Path. 

 Dept. Agric), expressed a doubt as to the advisability of using the ferrocyanide 

 test. 



